Process of obtaining ammonium sulfate.



sa a rns iii-v r in sh ll/i I GEBHARD NICOLAAS VIS, (2F (TUISE-LATIISTTE, FIEtANCE.

PROCESS OF OBTAINING AMMONIUM SULFATE,-

No Drawing.

I To all whom itma concern vented a new and useful Process of Obtaining Ammonium Sulfate; and I do hereby declare that the following is a full, clear,

and exact description of my invention, whichfwill enable ,-others skilled in the art to which appertains to make and use the same.

In my specification Serial Number631799 have men-' tioned that ammonium carbonate in the solid application filed June 7th, 1911, T

state mixed with gypsum (hydrated sulfate of calcium) with the addition of waterin a quantity which is not sufiicient to dissolve the amount of ammonium sulfate corresponding-to the ammonium carbonatei's entirely converted into ammonium sulfate if the amount of gypsum presentis sufiicie'nt.

On the other hand I have mentioned thatthis conversion in an aqueous solution oc-- curs at any temperature, even if the solution is saturated with ammonium sulfate. On this basis the process may be carried out very advantageously in the following manner Example: Gaseous ammonia is passed into a saturated solution of ammonium sulfate until to gr. of ammonia (NI-I are taken up per liter, which taking up of the ammonia is ascertained by means of titration,

after which carbonic acid is passed into the liquid, and care is taken that any ammonia that may have been carried away is retained in an absorption vessel. When passing carbonic acid into the liquid it is of advantage to cool same, so that the temperature remains below 25, because although the quantity of ammonium carbonate per liter is not considerable, yet this substance is sufficiently volatile to cause appreciable losses when this precaution is notch-served. Carbonic acid 1s ntroduced under continuous stirring, until all the ammonia has been con-.

verted into carbonate, which can be easily ascertained by determination of the carbonic acid in a. measured quantity of the liquid. It will-of course be obvious that the am-.

monia gas and the carbonic acid can be introduced simultaneously. After this the quantity of gypsum corresponding to the Specificationof Letters Patent.

Application filed January 27, 1913. Serial No. '2' .&,5li5=.

amount of ammonia added. in powdered condition, taking notice Oil tne fact that 5 gr. of ammonia per liter of liquid are not converted; this is done in order not to unduly protract the reaction. if, therefore, at the outset 5 cubic meters of satin rated ammonium sulfate solution was enr' ployed into which. was passed. 45 gr. of ammonia per liter, i060 kilograms of ground gypsum (of 95 per cent. CaSO,+2H,O) are added. and the mixture is gradually heated under continuous stirring to 40, which temperature is kept constant for 5 to 6 hours. It will then be found that up to about 5 gr. of ammonia. (in the form of carbonate) re main unconverted per liter, while the greater part of the ammonium sulfate formed to gether with calcium carbonate remains undissolved. The liquid is then heated almost .to boiling point and filtered. From the filtrate on cooling about 600 kilograms of pure ammonium sulfate is separated, which need only be drained and dried in order to give a first class article of commerce.

' The calcium carbonate is washed out with hot water and the wash waters are concentrated for crystallization. The mother liquor filtered off from the ammonium s fate is used over again to be treated with ammonia gas and carbonic acid.

Having fully described my invention, what I desire to claim, and secure by Letters Patent of the United States, is

The method of manufacturing ammonium sulfate consisting in preparing a concenand using the mother-liquid over again in repeating the process, substantially as de scribed.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

- GERHARD NICOLAAS VIS.

Witnesses: Amirnn GA'rALA, Tnno. GLEUCK.

Copies of-thls patent may be obtained for flvecents each, by addressing the Commissioner of Patents,

'Washington, I). 0.

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